System and method for precise beam positioning in ocular surgery

Abstract

A system and method for ocular surgery includes a delivery system for generating and guiding a surgical laser beam to a focal point in a treatment area of an eye. Additionally, a contact device is employed for using the eye to establish a reference datum. Further, an optical detector is coupled to the beam path of the surgical laser to create a sequence of cross-sectional images. Each image visualizes both the reference datum and the focal point. Operationally, a computer then uses these images to position and move the focal point in the treatment area relative to the reference datum for surgery.

Description

FIELD OF THE INVENTION[0001]The present invention pertains generally to systems and methods for performing ocular surgery. More particularly, the present invention pertains to computer-controlled laser surgical systems. The present invention is particularly, but not exclusively, useful as a system and a method that incorporate optical coherence tomography (OCT) techniques for the purpose of imaging both a treatment area and a reference datum, to control laser beam focal point movements within the treatment area during a surgical operation.BACKGROUND OF THE INVENTION[0002]When using a laser beam to perform ocular surgery, the precise movement of the laser beam's focal point through the tissue to be altered is absolutely imperative. Specifically, focal point position accuracies within about ten microns (10 μm) are preferable. To do this, the desired path for the laser beam's focal point must have a precisely defined start point. And, the laser beam's focal point must then be moved alo...

AI Technical Summary

Benefits of technology

[0008]A computer (i.e. a data processor) is electronically connected to both the beam delivery system and to the optical detector. With these connections, the computer is able to compare the location of desired focal points in the treatment area (based on pre-planned data for the surgery) with actual focal points. Deviations of actual focal points from desired focal points (i.e. error signals) can thus be identified. Using well known closed loop feedback control techniques, the delivery system is then adjusted to nullify or minimize the error signals. Consequently the system can be controlled to have its focal point follow a predetermined path through the treatment area. Alternatively, the system can be operated in an open-loop mode. If so operated, the focal point is moved to follow the predetermined path through the treatment area without any further adjustments. In the open-loop mode, however, it is still important to use the optical detector to establish an appropriate start point for the path of the focal point.

[0009]As indicated above, an important aspect of the present invention is its use of the optical detector to generate cross-sectional views of the treatment area. As envisioned for the present invention, such views can be sequentially made in real time. Further, they can be made from different perspectives, based on different cross-section planes through the eye. With these capabilities, the cross-sectional views can be used for control of the system, and they can also provide the operator with a three dimensional visualization of the treatment area. With this capability, it is envisioned that manual control over movements of the focal point in the treatment area is possible for the present invention. When used, manual control may either augment the computer control mentioned above, or provide an alternative to the computer control.

Problems solved by technology

All of this, of course, cannot be done by merely an external examination of the eye.

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